The present invention relates to a method and a tool for dismounting and mounting a roller ring.
In known roller ring stands, in particular in the roller stands for rolling of bars and wires, the roller rings are clamped at the end side between two flanges of a partitioned supporting shaft. Both parts of the supporting shaft and thereby its flanges are pressed together by a pulling anchor arranged in the axial region. The pulling anchor is under a high pretensioning in an axial direction. Therefore the roller ring is reliably held by the parts of the supporting shaft and the driving torque is transmitted between the supporting shaft and the roller ring without a relative movement. If such a roller ring is worn out or another caliber opening is needed, the roller ring must be exchanged. The present invention therefore more particularly deals with a method of dismounting and mounting of such a roller ring of a roller stand, which roller ring is held between two flanges of a partitioned supporting shaft by a pulling anchor with an axial pretensioning.
In a known method of this type, a first tool is placed first on the supporting shaft end facing away from the roller ring. The first tool is provided in its interior with a threaded sleeve which must be screwed manually on the pulling anchor and projecting outwardly from the supporting shaft end. This first tool is formed as a hydraulic cylinder-piston unit which is supported on the end surface of the supporting shaft end and on a projection of the threaded sleeve. Under the action of a load with a pressurized medium, the tool pulls through the threaded sleeve on the pulling anchor end, and thereby increases its pretensioning. However, the clamping nut of the pulling anchor is unloaded and can be now released by a manual turning by hand with a mandrel. The pressurized medium pressure of the placed first tool is removed and thereby the pulling anchor is unloaded with released clamping nut from any pretensioning. The placed first tool is removed and a second tool is screwed on the supporting shaft and coupled with it in the longitudinal direction. In contrast to the first tool, the second tool instead of the threaded sleeve has a pressure pin with an end surface pressing against an end surface of the pulling anchor end when the second tool is loaded with pressure of the pressurized medium.
With the released clamping nut, the pulling anchor can be displaced in an axial direction, and with this displacement movement the flange of the partitioned supporting shaft can be released from the end surface of the roller ring, and thereafter the second tool can be screwed from the supporting shaft end. Though the flanges of the supporting shaft are released from the roller ring, the rubber ring cannot be removed in the axial direction, being prevented by the pulling anchor which extends through the inner opening of the roller ring. With a third tool which engages again on the pulling anchor end facing away from the roller ring, the pulling anchor must be unscrewed by turning from each supporting shaft part arranged on the opposite side of the roller ring. Then, in some cases with a fourth tool, the free pulling anchor end can be pulled and thereby the other previously screwed-in pulling anchor end can be pulled out of the inner opening of the roller ring, so that it can be withdrawn in a radial direction from the gap space between the flanges. The mounting of the new roller ring is performed in a corresponding manner, but in accordance with an opposite sequence.
This known method of dismounting and mounting of the roller ring is relative expensive, since it must involve several different tools and extensive manual manipulations which are caused in particular by the multiple connection of the different tools with the supporting shaft ends and the pulling shaft ends or disconnection of the different tools from these ends. As a result, the known method is complicated and time consuming for personnel.